// 8.2 Renvoie un int dans l'intervalle [0..N[
// soit N valeurs différentes de 0 à N-1
int alea_int(int N) { return (int)(N*alea_float()); }
//============================================================== ARC_AROUND
struct particle arc_around(struct swarm sw, struct particle p)
{ // Build a tour, asking opinion of other particles for each arc
double big_value;
int candidate[Nmax];
double candidate_penalty[Nmax];
int candidate_nb;
double c_max;
int i;
int j;
int k;
//int m;
int node1,node2;
double penalty;
struct particle pt;
double r;
int rank;
int used[Nmax]= {0};
big_value=G.N*G.l_max;
pt=p;
node1=0; // The new tour begins in 0
rank=1;
used[node1]=1;
next_node:
candidate_nb=0;
for (node2=0; node2<G.N; node2++) // For each possible new node ...
{
if (used[node2]>0) continue;
if(rank==G.N-1) goto set_node; // Last node => no choice, anyway
penalty=0;
for (j=0; j<sw.size; j++) // ... ask opinions
{
for (k=0; k<G.N-1; k++) // Find the arc in the current particle, if exists
if (sw.p[k].best_x.s[k]==node1 && sw.p[k].best_x.s[k+1]==node2 )
{
penalty=sw.p[k].best_f;
goto next_opinions;
}
// Can't find it in the current particle
penalty=big_value;
next_opinions:
;
}
// Mean value
candidate_penalty[candidate_nb]=penalty/sw.size;
candidate[candidate_nb]=node2;
candidate_nb=candidate_nb+1;
} // next node2
// Choose the new node at random, according to penalties
c_max=0;
for (i=0; i<candidate_nb; i++) c_max=c_max+ candidate_penalty[i];
for (i=0; i<candidate_nb; i++) candidate_penalty[i]=1-candidate_penalty[i]/c_max; //Proba
for (i=1; i<candidate_nb; i++) candidate_penalty[i]=candidate_penalty[i-1]+candidate_penalty[i]; // Cumulate
r=alea_float(0,candidate_nb-1); // random choice
//printf("\n %i: ",candidate_nb);for (i=0;i<candidate_nb;i++) printf(" %f", candidate_penalty[i]);
for (i=0; i<candidate_nb; i++)
{
if(r<candidate_penalty[i])
{
node2=candidate[i];
goto set_node;
}
}
set_node:
// printf("\n r %f, i %i node2 %i",r,i,node2);
pt.x.s[rank]=node2; // Add the node
used[node2]=1; // remember it is already used
rank=rank+1;
if (rank<G.N) goto next_node;
pt.x.s[G.N]=pt.x.s[0]; // Complete the tour
pt.f=f(pt,-1,-1); // evaluate
if (pt.f<pt.best_f) // eventually update the best previous position
{
pt.best_x=pt.x;
pt.best_f=pt.f;
pt.best_time=time;
}
if (trace>1)
{
display_position(pt,1);
display_position(pt,2);
}
BB_update(pt); // Update the blackboard
return pt;
}